The Old English, Old Saxon (dumb), Gothic (dumbs), and Old Norse (dumbr) forms of the word meant only "mute, speechless;" in Old High German (thumb) it meant both this and "stupid," and in Modern German this latter became the only sense. Meaning "foolish, ignorant" was occasionally in Middle English, but modern use (1823) comes from influence of German dumm. Related: dumber; dumbest.

Applied to silent contrivances, hence dumbwaiter. As a verb, in late Old English, "to become mute;" c.1600, "to make mute." To dumb (something) down is from 1933.

Example Sentences for dumbest

"Deppy, you are the dumbest creature I know," exclaimed his wife.

Oh, don't you know that family affection's the dumbest thing on earth?

I supposed that eventually they'd pick the dumbest day laborer in the place and make him the patsy.

But if Zelda and these other catatonics are teaching ghosts, these ghosts are the dumbest jerks anywhere.

The Grootenheimers always was the dumbest family in the township, an' Elizabeth Grootenheimer is the dumbest of 'em all!

"The dumbest, woodenest, most conscientious young female person it has ever been my lot to meet," goes on Mr. Mills.

He can get away with faking, but the dumbest jury in the world would know what receiving stolen goods was, and he knows it.

He is the dumbest kind of a dumb fool that ain't king in some little corner.

He's always been considered the dumbest one in all our relations—never did know how to act.